Oxidation of the hardened inner surface of a pump liner to facilitate its removal from the liner



2,494, 791 PUMP INER Sheets-Sheet l URFACE OF FROM THE L NOLDY D INNER S REMOVAL F. AR

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Jan. 17, 1950 R. F. ARNOLDY 2,494,791

OXIDATION OF THE DENED INNER SURFACE OF A PUMP LINER TO FACILIT E ITS REMOVAL FROM THE ER Filed Oct. 29, 1943 beets-Sheet 2 I g I8 I I I I I I I I I I I I5 I I I I I3 I I I2 I4 I I I I I I I l ,5 I IOJI l I I 5" a I i i -1, 6 I IQ REARNOLDYI SQ G. CM.

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Patented Jan. 17, 1950 UNITED STAT ES O F 2,494,791 V i OXIDATION on THE HARDENED INNER SUR- FACE on A PUMP LINER To EACILITATE. rrs REMOVAL FRQMTHE LINER R ma F. Ar oust n, Tex.- Application October 29, 1943, Serial No. 508,266

V 1 Claim. o1. 1481431) In various arts tubular members are used invention has particular application to what are,

known as slush pump liners which is the inside liner of a reciprocating pump used for the circulation of an abrasive slush and mud in the rotary method of drilling wells.

The piston reciprooates in these liners pumping a medium of abrasive material and the liner is subjected to considerable wearand often be-.

comes scored or worn in such a manner that it is no longer serviceable. These liners come in various sizes and it has been found that if the hard internal surface can be economically removed, then the surface can then be reworked and provided with an additional hardened face of a slightly larger diameter than the original liner and that under these circumstances the liner can again be put in service.

The hard surfacing referred to may or may not be a ferrous metal in combination with chromium or boron and nickel. Other types in? clude cobalt, chromium, tungsten alloys and boron bearing steels or other suitable materials. For purposes of illustration these will be generally designated as hardsurfacing or facing materials which Will oxidize, but it is intended that this term shall apply to any of these hard surfacing materials. One rather general composition may be substantially 89% of iron, 4.8% of nickel, 3.2% of carbon and ,8% of boron. Other types of hard wear resistant substances may be used so 1 ong as it is a materialwhichmay be treated with a temperature below the melting point of the base metal such as steel of the liner.

It is one of the objects of the invention to treat a tubular member having a hardened surfact in such a manner that the surface is destroyed insofar as the composition of the hard material is concerned, with a view to reducing the hard material to a different composition which may be softer in the scale of hardness or which, because of its physical structure can be readily machined in order to remove the layer of such material from the inside of the liner or tubular member.

Another object of the invention is to oxidize a hardened surface inside of a tubular member so as to facilitate its removal.

another ject of t e nven io to eat a s i f r n d ater a by e in t be hhr m e 2. 0 F a d then ci g a t m.

carrying an excess of oxygen over the surface so. as to effect the oxidation thereof and a change in the composition of the suria ce in order to.

facilitate its removal.

Other and furtherobjeots of the inventio'nwill be readily apparent when the following descripo s o i r in n c on w t the ac.- companying drawings, wherein:

Fig 1 is c tr r ica sec i na e o furnace and illustrating the general arrangena d o s ctiqh i he parts.

i 2 and 3 re se tions. ake on the line 2-? and 3-.-3 hei lleotively of Fig. l.

Fig. 4 is. a sectional view similar to Fig. 1 but showing a modified arrangement for radir on r di ution o h a ed flui s a in th liner surface.

While the invention will be described in (16-.- ail and a li to a slush pump liner, it is to be understood that the process and apparatus ay he a p ede ua ly a w l t a t of tubular member which is provided with a hardeaed fa e either on the ins e or the outd here f.

e. ur a e used in treat n the liners is best en in sl and cqmrzr ses abas 2 which y be made up in any suitable manner, that shown being GOmPQS d, of ohannels 3 which have been filled with a concrete 4. It seems obvious, however, that any type of covering or supporting sur face can be used upon these channels 3. This base is seen in Fig, 3 being rectangular but i may be of any size or shape. Disposed upon his bas i a floo 5 m de up o two laye s o suitabl fireeproof briclgs or members 6.

These bricks are shown as arranged in ope Doslte direction so as to form a sturdy support for the wall sections 1 and 8 which are disposed thereon.

The lower wall section is made up of a plurality of courses of fireebrick, which are shown in Fig. 2 as being of a shape that they may be arranged in circular arches I I], four of which are seen in Fig. 2. It will be noted that these firebrick are tapered with the narrow face inward so as that a plurality of them will form a suitable surface.

The inside arch or tier ll of these bricks defines a mixing chamber it? which is circular and of a length e ual t the he ehth o the two courses of the bricks.

Fig. 2 shows thismixing chamber l2 as having the entries I3 and I4 thereinto from the fines I5 which extend to the outer periphery I! of the wall section.

These flues I5 are arranged to form a passage for the products of combustion from the burners I8 which are shown as being directed into the passage by the lines I9. The burner I8 is seen in elevation in Fig. 1 and has a plurality of openings therein so that a uniform blast of heated gases will be directed into the flue l5.

It should be noted that these flues I3 and I4 enter the mixing chamber I2 in a tangential direction so as to set up a circular or whirling motion of the gases in the chamber. These gases will rise and pass out of the top of the mixing chamber I2.

' the period of application of this hot air may be forty minutes to one hour. After this treatment the liner may be allowed to cool or may be removed so as to cool in air. No quenching of the liner is desired.

' It has been found that this treatment of the liner or other member affects the hard surface.

In order to provide a blast of air and an excess of oxygen in the mixing chamber to pass into the liner thereabove, an additional inlet 23 is provided in the form of a pipe of considerable diameter which passes through the base 2, the floor 5, and enters the chamber I2 in an axial direction. This blast of air may be suitably heated at a source not shown so that it may approximate a temperature of the gases entering the mixing chamber from the burners or the reaction and heat present in the chamber may effect the heating thereof.

It seems obvious that the air may be turned into the mixing chamber as desired, either before, during or after the heating by the fire from the burners.

The upper wall section 8 is very similar to the lower section 7 except that there are three arches of fire-brick and the heating or treating chamber is somewhat larger in diameter than the mixing chamber I2 and is of a greater length. The length and diameter of this chamber will depend on the liner or other member which is to be treated.

The area between the chambers I2 and 30 is a stepped construction providing a shoulder 3|, which forms a seat for the member which is to be treated.

Fig. 1 shows the liner 32 as having its lower end 33 seated on this shoulder 3! so that the gases and heated air from the mixing chamber I2 will be directed through the inside passage or area 33 in the liner.

In order to hold the liner 32 in proper position and to restrict the escape of the heated gases and air from the liner, a cap or cover plate 35 is shown as fitted into the upper end of the chamber 30. The handle 36 facilitates the insertion and removal of this cap or cover and the outlet passage 31 is shown as considerably restricted in order to confine the heat to the liner for the desired period.

It may be desirable to prevent any oxidation to the outer surface 40 of the liner while it is disposed in the chamber 30 and to this end an inlet 4| controlled by a valve 42 has been provided so that a suitable gaseous or liquid fluid may be applied to the outside of the liner and to fill the annular space 43 around the outside of the liner so as to prevent the oxidation thereof. Any suitable gas or liquid may be applied to this area to afford this protection.

The apparatus just described will be used and the method may be practiced by depositing the liner in position as shown in Fig. 1 and then turning on the burners so as to apply heat to the mixing chamber and to the inside of the liner. v

The excess of oxygen burns out the certain elements of the surface such as chronium, boron, carbon, etc. This leaves the surface or remaining material in a form which is much softer than or in a different physical state than the original hard-surfacing material which was in place on the member at the time the treatment was started. This surface may be in the form of a scale which may be readily be removable.

This treatment results in-the removal and/or destruction of the hard material and the next step after the cooling of the member is to then machine or otherwise remove the internal surface so as to remove such scale which results and to leave the surface in condition of a resurfacing operation or to machine it for use.

Another procedure may be to commingle the gas with an excess of air and introduce them simultaneously in order to provide an excess of oxygen to carry out the reaction. Thus sufficient oxygen is present for both combustion and reaction.

It might be well to state that it is the usual practice in manufacturing these liners to make the wall of a considerable thickness so that the liners may be used for the smaller size originally and then they maybe enlarged by reboring or relining on several occasions so as to obtain the maximum of life and service from each individual liner. Of course when the liner is resized, then oversized pistons or other members which work in the liner will be used.

With liners which have been surfaced with these hard materials which are not readily machinable, it has been difficult to reuse the liners after the surface became worn or scored. The cost and trouble required to remove a hard surface such as has'been applied to these liners was not only difficult, but uneconomical. By the treatment described herewith, it seems obvious that the hard surface is reduced to a softer surface which can be readily machined and the entire operation carried on satisfactorily so as to rework and reclaim the liner or other tubular member.

It is believed that the property or character of the hard material constituting the surface of the memberis changed to another state. The thickness of this hard surfacing material may vary from .030 to .060 of an inch and the treating process is intendedto be applied for a sufficient period of time to break up a surface of this thickness and tea depth such as will penetrate the hardened material to facilitate its removal.

Fig. 4 shows a slightly modified form of the furnace wherein'the parts are the same as shown in Fig. 1 except for the cap member 35 which has been slightly modified so" as to provide for a somewhat larger opening as at 50 which more nearly aproaches the inside area of the liner as at 33.

In some instances it may be that this area 33 is so large that the heated gases passing into the liner do not come in intimate contact with the Surface 32. With a view of reducing the area for passage of the gases and also to force the gases into more intimate contact with the surface 32 a support plate 5! has been provided having the handles 52 thereon to permit the handling thereof, and arranged with a rod or projection 53 which is shown in Fig. 4 as extending the full length of the liner. This projection may be made of a refractory material and as will be seen in Fig. 4 it causes the heated gases flowing from the burner 13 to be forced radially outward against the inside surface of the liner so that the heat will be radiated back and forth between the projection and the surface of the liner as such gases move upwardly through the liner. It has been found that a conductor of this sort greatly facilitates the heating operation as to the amount of heat required and the time of heating. The other parts of Fig. 4 are the same as previously described.

It seems obvious that any hard facing material which is aifected by a temperature below the melting point of the liner can be utilized and that heat as well as the oxidizing action may be used in combination together and the outside surface may be protected by a non-oxidizing atmosphere. The process has been particularly successful in the treatment of ferrous material containing boron.

Broadly the invention contemplates a method for treating slush pump liners and other tubular members which have been hard surfaced and where it is desired to remove such surface and possibly replace it with a harder surface having a slightly different size.

What is claimed is:

In the process of removing the boron-carbide hard surfacing from the inner periphery of the boron bearing base metal of a pump liner the steps of, heating the liner to approximately 2000 F, and passing air, heated to approximately the same temperature, through the inside of the liner for approximately forty minutes, whereby the carbide is converted to an oxide which can thereafter be readily removed.

ROMAN F. ARNOLDY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 745,432 Gohn Dec. 1, 1903 899,285 Bert Sept. 22, 1908 1,404,001 Barrett Jan. 17, 1922 1,416,865 Patch May 23, 1922 1,898,809 Berg Feb. 21, 1933 1,901,804 Davis et a1 Mar. 14, 1933 2,034,822 Morrow Mar. 22, 1936 2,081,612 Woodson May 25, 1937 2,097,298 Meyers, Jr. Oct. 26, 1937 2,116,228 Akin May 3, 1938 2,125,172 Kinzel July 26, 1938 2,356,329 Lundbye Aug. 22, 1944 OTHER REFERENCES Automotive Industries Magazine, Dec. 1, 1939, page 592. 

